The Fadnoun area, Tassili-n-Azdjer, Algeria: Fracture network geometry analysis

In the Fadnoun area, located in the Tassili-n-Azdjer region, a fracture network geometry analysis was carried out using the 2D geometry analysis technique. The area, situated on a Devonian plateau, is particularly suitable to study and model fractured media. The Fadnoun area and the faults associated with it are an excellent illustration of the Hercynian strain event. The use of linear reconnaissance, based on aerial photographs, and the analysis of fracture centers by the weight distribution method, has allowed setting up scale and general rules to characterize the fracture density. The scale and distribution rules that characterize the spatial distribution of fractures centers showed to be respectively consistent with a fractal character and obey a power law function. However, the curve of cumulative length frequency of fracture traces and the cumulative fracture spacing frequency for all fracture sets show a linear behavior and can be adjusted by a power law. The spacing law between the fractures for each fracture set direction shows a negative exponential distribution consistent with the clustered fractures model. The syn-fault joints tend to increase in frequency near the faults and we interpret the intensively fractured areas as a fault damage zone.